import Vue from 'vue';

Vue.directive('dialogDrag', {
  bind(el, binding, vnode, oldVnode) {
//弹框可拉伸最小宽高
    let minWidth = 400;
    let minHeight = 300;
//初始非全屏
    let isFullScreen = false;
//当前宽高
    let nowWidth = 0;
    let nowHight = 0;
//当前顶部高度
    let nowMarginTop = 0;
//获取弹框头部（这部分可双击全屏）
    const dialogHeaderEl = el.querySelector('.el-dialog__header');
//弹窗
    const dragDom = el.querySelector('.el-dialog');
//给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；
    dragDom.style.overflow = 'auto';
//清除选择头部文字效果
    dialogHeaderEl.onselectstart = new Function('return false');
//头部加上可拖动cursor
    dialogHeaderEl.style.cursor = 'move';

// 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);

    let moveDown = (e) => {
// 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - dialogHeaderEl.offsetLeft;
      const disY = e.clientY - dialogHeaderEl.offsetTop;

// 获取到的值带px 正则匹配替换
      let styL, styT;

// 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
      if (sty.left.includes('%')) {
        styL = +document.body.clientWidth * (+sty.left.replace(/%/g, '') / 100);
        styT = +document.body.clientHeight * (+sty.top.replace(/%/g, '') / 100);
      } else {
        styL = +sty.left.replace(/px/g, '');
        styT = +sty.top.replace(/px/g, '');
      };

      document.onmousemove = function (e) {
// 通过事件委托，计算移动的距离
        const l = e.clientX - disX;
        const t = e.clientY - disY;
        dragDom.style.left = `${l + styL}px`;
        dragDom.style.top = `${t + styT}px`;
      };
      document.onmouseup = function (e) {
        document.onmousemove = null;
        document.onmouseup = null;
      };
    }
    dialogHeaderEl.onmousedown = moveDown;
// //双击头部效果
// dialogHeaderEl.ondblclick = (e) => {
// if (isFullScreen == false) {
// nowHight = dragDom.clientHeight;
// nowWidth = dragDom.clientWidth;
// nowMarginTop = dragDom.style.marginTop;
// dragDom.style.left = 0;
// dragDom.style.top = 0;
// dragDom.style.height = “100VH”;
// dragDom.style.width = “100VW”;
// dragDom.style.marginTop = 0;
// isFullScreen = true;
// dialogHeaderEl.style.cursor = 'initial';
// dialogHeaderEl.onmousedown = null;
// } else {
// dragDom.style.height = “auto”;
// dragDom.style.width = nowWidth + 'px';
// dragDom.style.marginTop = nowMarginTop;
// isFullScreen = false;
// dialogHeaderEl.style.cursor = 'move';
// dialogHeaderEl.onmousedown = moveDown;
// }
// }

//拉伸
    let resizeEl=document.createElement('div');
    dragDom.appendChild(resizeEl);
//在弹窗右下角加上一个10-10px的控制块
    resizeEl.style.cursor = 'se-resize';
    resizeEl.style.position = 'absolute';
    resizeEl.style.height = '10px';
    resizeEl.style.width = '10px';
    resizeEl.style.right = '0px';
    resizeEl.style.bottom = '0px';
//鼠标拉伸弹窗
    resizeEl.onmousedown = (e) => {
// 记录初始x位置
      const clientX = e.clientX;
// 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - resizeEl.offsetLeft;
      const disY = e.clientY - resizeEl.offsetTop;

      document.onmousemove = function (e) {
        e.preventDefault(); // 移动时禁用默认事件
// 通过事件委托，计算移动的距离
        const x = e.clientX - disX + (e.clientX - clientX);//这里 由于elementUI的dialog控制居中的，所以水平拉伸效果是双倍
        const y = e.clientY - disY;
//比较是否小于最小宽高
        dragDom.style.width = x > minWidth ? `${x}px` : minWidth + 'px';
        dragDom.style.height = y > minHeight ? `${y}px` : minHeight + 'px';
      };
//拉伸结束
      document.onmouseup = function (e) {
        document.onmousemove = null;
        document.onmouseup = null;
      };
    }
  }
})
